Bacteria 18 4 Bacteria and Archaea KEY CONCEPT

Bacteria

18. 4 Bacteria and Archaea KEY CONCEPT Bacteria and archaea are both single-celled prokaryotes. TEKS 8 C

What are Bacteria? • Prokaryotes - Cells that do not have their DNA contained in a nucleus (All Bacteria!) • There are two Kingdoms of unicellular prokaryotic organisms: – Archaebacteria – Eubacteria (“eu” meaning true bacteria).

Archaebacteria • In their own domain Archaea because they are so different molecularly from true bacteria. – They are prokaryotic, unicellular and live in extreme environments (no oxygen, high salt, high temperatures, etc. ) – Their cells walls do not contain peptidoglycan.

Eubacteria • In the Domain Bacteria. – They are prokaryotic, unicellular, and live all over the world, around, in and on organisms (yes, all inside of you!) – Their cell walls are made of peptidoglycan.

18. 4 Bacteria and Archaea • Bacteria and archaea have similar structures. – plasmid – flagellum pili plasma – pili membrance chromosome cell wall plasmid This diagram shows the typical structure of a prokaryote. Archaea and bacteria look very similar, although they have important molecular differences. TEKS 8 C flagellum

Parts of Bacteria 1. Plasma (cell) membrane- selectively permeable for material exchange 2. Cell Wall- made of peptidoglycan in Eubacteria 3. DNA- contained in a “nucleoid region” 4. Pili- small protein extensions used to anchor themselves OR sex pili aid in exchanging DNA 5. Flagella- whip-like tail for movement 6. Ribosomes- translate genetic material into proteins

18. 4 Bacteria and Archaea TEKS 8 C Prokaryotes are widespread on Earth. • Prokaryotes can be grouped by their need for oxygen. – obligate anaerobes are poisoned by oxygen – obligate aerobes need oxygen – facultative aerobes can live with or without oxygen

18. 4 Bacteria and Archaea TEKS 8 C Bacteria and archaea are structurally similar but have different molecular characteristics. • Bacteria commonly come in three forms. – rod-shaped, called bacilli – spiral, called spirilla or spirochetes – spherical, called cocci Lactobacilli: rod-shaped Spirochaeta: spiral • Archaea have many shapes. Enterococci: spherical

Coccus Spirillum Bacillus

18. 4 Bacteria and Archaea TEKS 8 C • Bacteria and archaea have molecular differences. – The amount of peptidoglycan within the cell wall can differ between bacteria GRAM NEGATIVE GRAM POSITIVE – Archaea have different lipids entirely

Classification- Gram staining • Bacteria are identified by how THICK their cell wall is. Scientists use a method called Gram staining to identify certain kinds of bacteria. – Gram + : bacteria stains purple, meaning they have a thick cell wall of peptidoglycan – Gram - : bacteria stains light pink (or red), meaning they have a thin wall of peptidoglycan

18. 4 Bacteria and Archaea • Gram staining identifies bacteria. – stains polymer peptidoglycan – gram-positive stains purple, more peptidoglycan – gram-negative stains pink, less peptidoglycan Gram-negative bacteria have a thin layer of peptidoglycan and stain red. Gram-positive bacteria have a thicker peptidoglycan layer and stain purple. TEKS 8 C

Metabolism • Bacteria can be classified by how they obtain energy and use it. They can be… – heterotrophs (must consume food) – autotrophs (can make their own food). • Chemoautotroph – make their own food starting with inorganic molecules • Photoautotroph – make their own food using light

Reproduction • Most bacteria reproduce very quickly by a process called binary fission, some only taking 20 minutes to divide. • They reproduce asexually, meaning they simply divide without combining genetic material. • Small parts of DNA can be exchanged through sex pili. They act like little tunnels through which DNA can be exchanged.

18. 4 Bacteria and Archaea TEKS 8 C Bacteria have various strategies for survival. • Prokaryotes exchange genes during conjugation bridge • Bacteria may survive by forming endospores. TEM; magnification 6000 x

18. 5 Beneficial Roles of Prokaryotes KEY CONCEPT Prokaryotes perform important functions for organisms and ecosystems. TEKS 11 C

Importance of Bacteria • We think of bacteria as being all bad, but actually we need them greatly! • Bacteria are vital to maintaining the living world.

Human uses • We have bacteria living on all surfaces of our bodies and ones such as E. coli are essential for our digestion. We provide them with a warm environment, and they provide us with essential vitamins that we cannot produce on our own. This too is a mutualistic symbiotic relationship.

18. 5 Beneficial Roles of Prokaryotes • Bacteria help ferment many foods. – yogurt, cheese – pickles, sauerkraut – soy sauce, vinegar TEKS 11 C

18. 5 Beneficial Roles of Prokaryotes play important roles in ecosystems. • Prokaryotes have many functions in ecosystems. – photosynthesize – recycle carbon, nitrogen, hydrogen, sulfur – fix nitrogen TEKS 11 C

Importance 2. Decomposers: when all organisms die, their organic matter must be returned to the soil for other organisms. Decomposers complete the carbon cycle.

Pathogens- harmful bacteria • Any disease causing agent is called a pathogen- it could be bacterial or viral • Harmful Bacteria-cause disease in one of two ways: – Breaking down our body’s cells as food – Releasing toxins that travel through the body and damage our cells

18. 6 Bacterial Diseases and Antibiotics TEKS 7 F, 11 C Some bacteria cause disease. • Bacteria cause disease by invading tissues or making toxins. • A toxin is a poison released by an organism.

18. 6 Bacterial Diseases and Antibiotics TEKS 7 F, 11 C • Normally harmless bacteria can become destructive. – may colonize new tissues

18. 6 Bacterial Diseases and Antibiotics TEKS 7 F, 11 C • Normally harmless bacteria can become destructive. – immune system may be lowered

Lyme Disease l l Cause: Borrelia burgdorferi Symptoms: fever, fatigue, headaches, muscle aches, joint aches, Bulls-eye shaped rash Transmission: tick bite Treatment: antibiotics

Tetanus (Lock jaw) l l l Cause: Clostridium tetani Toxins released by bacteria interfere with nervous system Symptoms: Severe muscle spasms and possibly death Transmission: Commonly contracted from deep puncture wound or self-piercing with contaminated materials

Tetanus (Lock jaw) l Treatment: – – – Clean wound Mild: given antibodies against it, with antibiotics, and a vaccine Severe: same as above, muscle relaxers or even paralytic drugs to stop the spasming

Tuberculosis (TB) l l l Affects nearly 1/3 of the world’s population Cause: Mycobacterium tuberculosis Symptoms: Fatigue, weight loss, fever, chronic cough Tubercles form in lungs (dormant form) Transmission: Spread through cough Treatment: long term antibiotic treatment (6 -12 months)

Gonorrhea l l Cause: Neisseria gonorrhoeae Male symptoms: – – – l Thick, foul-smelling discharge from penis Painful urination Testiculur and abdominal pain Female symptoms: – – – Pus-like vaginal discharge Pain urinating Bleeding after intercourse l l Transmission: oral, anal, or vaginal sex Treatment: with antibiotics

Chlamydia l l l One of the most common STIs on college campuses Cause: Chlamydia trachomatis Symptoms: Burning during urination, discharge from the penis or vagina, pain and itching l l Transmission: oral, anal, or vaginal sex; mother to child during childbirth through vaginal canal Treatment: with antibiotics

Strep Throat l l l Cause: Streptococcus pyogenes, certain strains cause scarlet fever and Toxic Shock Syndrome Symptoms: fever, sore throat, swollen glands Transmission: respiratory droplets (coughing sneezing) Treatment: antibiotics can cause it to go away faster Purple gram +

Tooth Decay l l Cause: Streptococcus mutans, bacteria doubles in 24 hours Symptoms: Destruction of tooth enamel Transmission: resident in mouth Treatment: brush and floss daily

Bacterial meningitis l l Cause: Neisseria meningitis Symptoms: high fever, headache, stiff neck, nausea, fatigue Transmission: most common in college dorms Treatment: antibiotics, early detection is essential

Anthrax l l Used in Bioterrorism Cause: Bacillus anthracis, a spore-forming bacteria Transmission/Symptoms of varying types: – Spread by eating undercooked meat (vomiting and diarrhea, possible death) – breathing in spores (usually fatal) – skin contact (ulcers, rashes, not fatal) Treatment: oral and IV antibiotics

Botulism- food poisoning l l l Cause: Clostridium botulinum Symptoms: blurred vision, slurred speech, difficulty swallowing, muscle weakness, paralysis Transmission: From a wound, contaminated food Treatment: antibiotics FACTOID: Botox is a toxin secreted by Clostridium botulinum

Staphylococcus aureus l l Pets can carry bacteria as well! Staphylococcus aureus – – Gram + Cause: Staphylococcus aureus Symptoms: nausea, cramping, retching; some individuals may not show symptoms Transmission: eating contaminated food, contaminated air, individuals and surfaces l PETS!

Preventing Disease 1. Good hygiene- wash hands thoroughly with soap and water (you don’t need antibacterial!!!), brush teeth and floss (bacteria in your mouth DOUBLES in 24 hours); take care with who your drink after, check ups at the doctor

Preventing Disease 2. Vaccine- a weakened or dead form of the pathogen is given to a patient whose body will form an immune response to it. Once that immune response happens, your body remembers it forever and if the real pathogen gets in your body, your immune system will react quickly and kill it immediately.

Preventing Disease 3. Antibiotics- if infection does occur, antibiotics can be given. They prevent growth and division of bacteria so that our immune systems can conquer the illness more easily. Unfortunately, bacteria evolve in response to this pressure and we have many antibiotic resistant diseases now.